System justification theory proposes that individuals develop belief systems to explain and legitimize existing status differences between groups in societies. Although people differ in the extent to which they endorse system-justifying beliefs, research shows they are widely endorsed and have important implications for mental health. In particular, recent research has found that system justification is related to mental disorders among members of low-status groups. However, the current research is limited by its focus on college samples and use of cross-sectional methods. The long-term objective of this application is to extend the current research on system justification by examining system justification as a risk factor for mental illness among low-income racial/ethnic minorities and recent immigrants, exploring relationships longitudinally and studying associations between maternal system justification and mental health and child behavior problems. The current project, comprised of two studies, relies on data from NYU's Center for Research on Culture, Development and Education (CRCDE), which have a number of advantages. First, the sample is composed of 200 low-income, immigrant and ethnically diverse women who recently gave birth in New York City. Second, mothers and their infants are followed longitudinally over three years and assessed using well- validated epidemiological screening tools for maternal mental disorders and child behavior problems. Third, the CRCDE combines quantitative survey measures with an embedded qualitative study of a random sample of survey members, allowing for a more nuanced understanding of relationships between constructs. The first study, focused on survey data, employs regression-based change score analyses and structural equation modeling techniques to explore longitudinal associations between maternal system justification, maternal mental illness and child behavior problems. I hypothesize that system justification will be positively related to maternal risk for mental illness and child behavior problems. The second study employs a mixed-methods approach, combining survey and qualitative data to explore the types of system- justifying beliefs endorsed by diverse low-income women, and identify factors that mitigate or exacerbate the relationship between system justification, maternal mental disorders and child behavior problems. The proposed project has direct implications for public health. System justification may be an important previously unidentified risk factor placing mothers and their children at risk for mental disorders and behavior problems. Understanding the role of system justification in mental health can inform policy and intervention efforts aimed at improving the mental health of vulnerable groups in the US.